Non Technical Summary Strawberries are of great economic importance to producers in Florida and California due to strong consumer demand 12 months of the year for the product. The crop is intensively cultivated and requires large inputs of chemicals including insecticides. The project will identify the insect problems on strawberry and will develop an integrated pest management (IPM) scheme to control harmful insects through targeted release of reared beneficial insects. This will result in greatly reduced requirements for insecticides on strawberry crops.

Goals / Objectives The objectives of the work follow. 1. Greenhouse research trials on strawberries with beneficial insects will be direct issues of application rate and timing method of application 2. Field trials to evaluate and demonstrate efficacy in commercial strawberry production 3. Economic assessment of the cost in comparison with the use of insecticides 4. Outreach in which the results of the greenhouse and field tests will be disseminated to Extension agents, growers for new printed and web-based publications, meetings and field days, will be completed

Project Methods We propose to apply a total system approach for insect management of strawberry by release of insects with broad control over the insect pests. IPM scouting using current protocols will be critical to assess insect pest problems on the crop. Spider mites will be controlled by release of predatory mites following current practice. As Orius sp., G. punctipes and C. maculata are known to control two spotted mites, we will evaluate the potential of these insects as an addition or replacement for P. persimilis. Lepidopteran larvae will be targeted with Bacillus thuringienisis as they are now, or G. punctipes may be a suitable alternative as the nymphs go down into the crowns and consume the larvae. C. maculata and/or G. punctipes will be used for control of aphids. Orius spp. will be released for control of thrips, and additional control of spider mites. Sanitation, or removal of old fruit from the pathways should effectively prevent sap beetles and fruit flies (Drosophila
sp.), however this may not be an economic alternative, especially towards the end of the growning season as prices fall. A major problem in strawberry production is fruit rot caused by fungal diseases. This proposal will not reduce this problem, and it is anticipated dthat fungicide sprays as biorational compounds will continue to be necessary. The survival of the biocontrol insects in the presence of biorationals (and fungicides) will be evaluated and only compatible compounds will be used.

Progress 09/15/01 to 09/14/04

OutputsCage Greenhouse trial. This study was conducted to validate the laboratory studies. Five strawberry plants were infested with adult female aphids and placed into a meter cubed nylon covered cage. Three cages were infested with 5 aphids per plant, three cages with 10 aphids per plant, and three cages with 15 aphids per plant. After one week the aphids on one labeled stem per plant were counted. The pink spotted lady beetles 3rd instar or adult were introduced into the cage at 1, 3 and 5 days of application. Three 3rd instar or adult of the pink spotted lady beetles was the optimum release rate. Development of a sampling protocol for strawberry. Sampling protocols were already established for monitoring the two-spotted spider mite (TSM) and predatory mites in strawberry. Aphids and TSM were scouted on a weekly basis throughout the duration of the crop. We counted pest and natural occurrence of predators or other natural enemies. Entomos closed December 19, 2002 and the
availability of predators for the research was limited due to no availability of the pink spotted lady beetle on the market. Entomos was the only company in North America producing commercially the pink spotted lady beetle. Field trials. This part of the research was conducted on farms of cooperating growers. A systematic scouting protocol was conducted based on the examination of 100 leaflets taken at random from across the field. The pink spotted lady beetle, bigeyed bug and minute pirate bug were not released. Economic evaluation. Data was taken to compare the production costs of strawberry grown with beneficials and with insecticides. The model chosen for this analysis was the TSM-predatory mites (Phitoseiulus persimilis Athias-Henriot). A similar model using the pink spotted lady beetles has not been developed. Outreach. Results from this research were delivered to producers through the University of Florida system (strawberry.ifas.ufl.edu, edis.ufl.edu). We participated in 2
mini-field days, growers meetings, and national and international professional meetings.

ImpactsThe pink spotted lady beetle, bigeyed bug and minute pirate bug feed on aphids and TSM when using strawberry as substrate. The pink spotted lady beetle offers the most efficient and consistency of pest control. Strawberry producers could rely especially on 3rd instar pink spotted lady beetle as a quick control method in the greenhouse. There are some advantages of using the pink spotted lady beetles for pest control: they can become established in their crops if released early in the season, and also, resistance will not occur as with chemical insecticides. If early detection of the pest is made, based on intense scouting data, the pink spotted lady beetle may lead to the total elimination of the pests; as a consequence, the use of insecticides or miticides would decrease, creating a safer environment and reduced cost of production. Overall, results from this research contribute to the scientific knowledge necessary to manipulate generalist predators in many plant
production systems.

OutputsThe objective of the overall project is to reduce the use of pesticides on strawberry production by targeting arthropod problems through early releases of Coleomeiglla maculata DeGeer, Geocoris punctipes Say, and Orius insidiosus (Say). The first year involved research on the biological interaction (feeding, choice studies) of the three predators and some strawberry pests such as the melon aphid, Aphis gossypii Glover (Homoptera: Aphididae), and the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). The second year involved complementary laboratory experiments (time and rate of release, predator competition), and greenhouse trials (time and rate of release). Third year will engage experimental station and on-farm trials in the Plant City/Dover area where 95% of the strawberries are grown in the state of Florida.

ImpactsResults from our experiments provided the basis to determine the number of beneficials that need to be release in order to provide adequate control. We believe that C. maculata will be an important addition to the biological control complex already in existence in the strawberry crop ecosystem. If early detection of the pests are made, based on intense scouting data, C. maculata would lead to the almost total elimination of the pests; as a consequence, the use of insecticides or miticides would decrease. In general, the advantages of using these beneficials for pest control are: (1) beneficials can become established in their crops if released early in the season, and (2) resistance is not a problem. This reduction in chemical dependency will create a safer environment and it will reduce the cost of strawberry production. Information is already being shared with growers who are interested in implementing biological control. We have already had two field days
(www.hos.ufl.edu/Protectedag) where we provided growers with our latest findings. These activities will be held every year. We regularly participate with the Berry/Vegetable Newsletter (http://strawberry.ifas.ufl.edu) and the University of Florida Extension Information Service (http://edis.ifas.ufl.edu/). Regular updates on our web pages provide farmers with the necessary information for decision-making. Additional information is also being developed regarding potential benefit of these predators against other pests such as whiteflies, and sporadic pests such as squash bugs in greenhouses.

Rondon, S.I., D.J.Cantliffe, and J.F. Price. 2003. Thoughts on Biological Control of Insects in Vegetable Greenhouses. Berry/Vegetable Times. April I. University of Florida, Institute of Food and Agricultural Sciences. Gulf Coast and Research Center. http://strawberry.ifas.ufl.edu/.

Cantliffe, D.J., S.I. Rondon, and A.V. Paranjpe. 2002. Strawberry culture under protective structures and biological control of strawberry pests. Part II. Berry Times December 2:12. University of Florida, Institute of Food and Agricultural Sciences. Gulf Coast and Research Center. http://strawberry.ifas.ufl.edu/.

Cantliffe, D.J., S.I. Rondon, and A.V. Paranjpe. 2002. Strawberry culture under protective structures and biological control of strawberry pests. Part I. Berry Times November 2:11. University of Florida, Institute of Food and Agricultural Sciences. Gulf Coast and Research Center. http://strawberry.ifas.ufl.edu/.

OutputsStrawberry is an intensive cultivate high value crop that requires large inputs of insecticides. A series of experiments were carried out to demonstrate that commerical production with minimal use of insecticides through the use of biological control as part of an integrated pest management system is feasible. The feeding behavior of different generalist predators were studied under laboratory conditions. Three predators, the lady beetle (Coleomegilla maculata), the big-eyed bug (Geocoris punctipes), and the minute pirate bug (Orius insidiosus) were evaluated as potential biological control agents against some strawberry greenhouse pests. These pests include the cotton aphid (Aphis gossypii) and the two-spotted spider mite (Tetranychus urticae). The experiments included feeding, effectiveness, and predator:prey ratio studies for each predator instar and prey. Among the three predators, 3rd and 4th instar larvae of Coleomegilla proved the most effective against aphids
and mites. They consumed the greatest number of prey in the shortest period of time. Ongoing and future research will determine the effectiveness of these predators to control pests on strawberries grown commercially in greenhouses and open fields.

ImpactsThe option of production and integrated pest management systems in economical passive ventilated greenhouses will be developed and refined so that producers will have information on full season production of various crops without a need for methyl bromide and, potentially, the use of other harsh pesticides. Efficient greenhouse operations can produce up to 10 times more product volume compared to open field production (with plastic mulch and methyl bromide) and grow higher quality products during the entire year and of crops that, in some cases, cannot be grown profitably in the field. Moreover, water use will be greatly reduced and ground water pollution will be virtually eliminated. Pest control in a greenhouse in Florida poses a different set of challenges to that of pest control in the field or in greenhouses in more northerly regions. Effective biological control of insect pests is the result of the establishment of a population of beneficial insects to maintain
populations of pests below an economic threshold. Produce labeled as pesticide free could command a premium for the producer and create greater demand for the product at the retail level.

OutputsStrawberries are of major economic importance to the State of Florida. The acerage devoted to strawberries in Florida in 1999 was 6,200 acres, production was 1,860,000 cwt with a value of $150,666,000 (USDA, NASS, Vegetable Summary, 1999). The majority of intensive strawberry production is concentrated in west central Florida. Florida is the second largest producer of strawberries in the US, second only in dollar importance to California, and is the principal source of fresh market strawberries during the winter months. Unfortunately, like other highly coastal urbanized lands in the world, Florida has been facing a displacement and loss of the warmest, most productive lands for winter vegetable production. With the use of protective structures, crop yield per unit area can be increased and fruit quality improved. High value crops such as cluster tomatoes, colored peppers, Beit Alpha cucumbers, Galia muskmelon, and strawberry have been successfully grown in hydroponic
systems with biological control practices that minimize the use of pesticides. Beneficial insects, such as Coleomegilla maculata, Geocoris punctipes, and Orius insidiosous, introduced on strawberry in the greenhouse have consumed pests such as aphids, two-spotted spider mites, caterpillar larvae, thrips, and whitefly. All 3 species will consume eggs and the juvenile stages of the pests. The number of aphids consumed by both Coleomegilla maculata and Geocoris punctipes has been established in petri dish and cage trials and has been found to be similar, 2 individuals will consume 75 aphids over one week.

Impacts(N/A)

Publications

Cantliffe, D. and E. Jovicich. 2000. Vegetable production in the greenhouse: a worldwide growth phenomenon and an opportunity for research and graduate education. The 83rd Ann. Meeting of the Florida Entomological Society, Protected Crop Entomology Symposium, Aug. 6-9, 2000.